Comparative Pharmacology
Head-to-head clinical analysis: E MYCIN E versus E E S.
Peer-Reviewed Evidence
Head-to-head clinical analysis: E MYCIN E versus E E S.
E-MYCIN E vs E.E.S.
Head-to-head clinical comparison of therapeutic indices and safety profiles.
Erythromycin binds to the 50S ribosomal subunit of susceptible bacteria, inhibiting protein synthesis by blocking the translocation of peptide chains.
Erythromycin (E.E.S.) binds to the 50S subunit of bacterial ribosomes, inhibiting peptide chain elongation and protein synthesis. It also exhibits prokinetic effects on the gastrointestinal tract via motilin receptor agonism.
Treatment of infections caused by susceptible strains of microorganisms (e.g., respiratory tract infections, skin infections, pertussis, diphtheria, intestinal amebiasis)Prophylaxis of rheumatic feverOphthalmic neonatal conjunctivitis due to Chlamydia trachomatis
Treatment of acute otitis mediaTreatment of pharyngitis/tonsillitis due to Streptococcus pyogenesTreatment of pneumonia due to Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia trachomatisTreatment of pertussisTreatment of uncomplicated skin and skin structure infectionsTreatment of acne vulgaris (topical or systemic low-dose)Treatment of diphtheriaTreatment of syphilis (primary and secondary)Treatment of chlamydial infections during pregnancyTreatment of nongonococcal urethritisProphylaxis of recurrent rheumatic feverOff-label: improvement of gastric motility in gastroparesis
250-500 mg orally every 6 hours or 333-500 mg every 8 hours; maximum 4 g/day.
250-500 mg every 6 hours orally or 15-20 mg/kg/day IV divided every 6 hours.
None Documented
None Documented
Terminal elimination half-life is 1.5-3 hours in adults; prolonged to 4-6 hours in neonates and patients with hepatic impairment.
1.5-2 hours in adults with normal renal function; prolonged to 4-6 hours in patients with hepatic impairment; may be shorter in children.
Erythromycin is primarily metabolized by the hepatic cytochrome P450 enzyme system (CYP3A4) via demethylation.
Erythromycin is metabolized by cytochrome P450 3A4 (CYP3A4) enzymes; it also inhibits CYP3A4, leading to drug interactions.
Primarily excreted unchanged in urine (70-80%) via glomerular filtration and tubular secretion; 15-20% excreted in feces via biliary elimination.
Primarily hepatic (biliary) excretion of unchanged drug and active metabolites; approximately 15% of an oral dose is excreted unchanged in urine. The remainder is eliminated via feces as unchanged drug and metabolites.
70-80% bound, primarily to albumin.
75-80% bound primarily to albumin; binding is saturable and decreased in hepatic impairment.
0.6-0.9 L/kg; indicates extensive tissue penetration, including lung, tonsils, and middle ear fluid.
0.5-0.8 L/kg, indicating moderate tissue distribution; higher in infants (up to 1.2 L/kg).
Oral: 30-40% (erythromycin base is acid-labile); enteric-coated formulations: 40-60%.
Oral: 35-40% due to incomplete absorption and first-pass metabolism; intramuscular: 75-85%; intravenous: 100%.
No dose adjustment required for mild to moderate renal impairment. For severe renal impairment (eGFR < 10 mL/min), reduce dose by 50% or extend interval to every 12-18 hours.
No dose adjustment required; erythromycin undergoes minimal renal excretion.
Child-Pugh Class A: no adjustment. Class B: reduce dose by 50% or extend interval. Class C: avoid use or reduce dose by 75% and monitor closely.
Use with caution; reduce dose in severe hepatic impairment (Child-Pugh C) by 50%.
30-50 mg/kg/day orally divided every 6-8 hours; maximum 2 g/day. For severe infections, up to 75 mg/kg/day divided every 6 hours.
30-50 mg/kg/day orally divided every 6 hours; maximum 2 g/day.
Consider reduced renal function; monitor for QT prolongation and ototoxicity. Initiate at lower end of dosing range (250 mg every 6 hours) and titrate based on response and tolerance.
Increased risk of QT prolongation and torsades de pointes; use lowest effective dose. Adjust for renal function if eGFR < 10 mL/min.
Erythromycin has been associated with prolongation of the QT interval and rare cases of ventricular arrhythmias, including torsades de pointes, which can be fatal. Avoid use in patients with known QT prolongation, electrolyte abnormalities, or concurrent use of other QT-prolonging drugs.
Increased risk of QT interval prolongation and torsades de pointes, especially in patients with risk factors such as electrolyte abnormalities, bradycardia, or concurrent use of other QT-prolonging drugs. Fatal arrhythmias have been reported.
["QT interval prolongation and risk of cardiac arrhythmias","Hepatic dysfunction and hepatitis","Exacerbation of myasthenia gravis","Clostridium difficile-associated diarrhea","Allergic reactions including anaphylaxis","Superinfection with prolonged use"]
["QT prolongation and risk of cardiac arrhythmias (torsades de pointes); monitor electrolytes and avoid in patients with prolonged QT interval.","Hepatic toxicity (cholestatic jaundice) especially with estolate salt; monitor liver function.","Infantile hypertrophic pyloric stenosis (IHPS) reported in infants <6 weeks of age exposed to erythromycin; avoid use in this population unless essential.","Exacerbation of myasthenia gravis; use with caution in patients with neuromuscular disorders.","Clostridium difficile-associated diarrhea (CDAD); report any cases.","Ototoxicity (hearing loss) with high doses, especially in renal impairment.","Increased risk of cardiac death when used with drugs that inhibit CYP3A4 or prolong QT interval."]
["Hypersensitivity to erythromycin or any macrolide antibiotic","Concurrent use with terfenadine, astemizole, or cisapride due to risk of cardiotoxicity","Preexisting QT prolongation or history of ventricular arrhythmias"]
["Hypersensitivity to erythromycin or any macrolide antibiotic","Patients with known QT interval prolongation or history of torsades de pointes","Concurrent use with CYP3A4 substrates that prolong QT interval (e.g., cisapride, pimozide, astemizole, terfenadine) due to risk of fatal arrhythmias","Hepatic impairment (relative contraindication, especially with estolate salt)","Infants <2 weeks of age with certain infections (relative contraindication due to IHPS risk)"]
Data Pending Review
Data Pending Review
Take on an empty stomach: 1 hour before or 2 hours after meals. Avoid grapefruit juice as it can increase erythromycin serum concentrations and risk of QT prolongation. Avoid alcohol as it may increase hepatotoxicity risk. High-fat meals may delay absorption.
Avoid grapefruit juice (inhibits CYP3A4 metabolism, increases erythromycin levels). Take on empty stomach for optimal absorption; if GI upset, may take with small amount of food. Avoid concurrent ingestion of high-fat meals which may delay absorption.
E-MYCIN E (erythromycin) is classified as FDA Pregnancy Category B. No teratogenic effects have been demonstrated in animal studies, and adequate well-controlled studies in pregnant women have not shown fetal risk. However, data are limited; use during pregnancy only if clearly needed. First trimester: No evidence of increased risk of major malformations. Second and third trimesters: Considered safe; erythromycin is a first-line agent for Group B Streptococcus prophylaxis during labor.
Erythromycin ethylsuccinate (E.E.S.) is Pregnancy Category B. Animal studies have not demonstrated fetal risk, but no adequate controlled studies in pregnant women. Current evidence suggests no increased risk of major malformations. However, erythromycin base (oral) has been associated with a slightly increased risk of pyloric stenosis in infants exposed in utero, particularly in the first trimester. Use only if clearly needed.
Erythromycin is excreted into breast milk in small amounts (M/P ratio approximately 0.5-1.0). Breastfeeding is considered safe as concentrations are low and unlikely to cause adverse effects in the infant. However, caution is advised due to potential for gastrointestinal disturbances or sensitization. The AAP classifies erythromycin as compatible with breastfeeding.
Erythromycin is excreted into human milk in small amounts. The milk-to-plasma ratio (M/P) is approximately 0.5. Although generally considered compatible with breastfeeding, there is a potential for adverse effects such as gastrointestinal disturbances and alteration of infant gut flora. Caution advised, especially in neonates younger than 6 weeks, due to risk of hypertrophic pyloric stenosis.
No specific dosage adjustments are recommended during pregnancy. Pharmacokinetic changes (increased volume of distribution, altered clearance) are not clinically significant for erythromycin. Standard dosing (e.g., 250-500 mg PO QID) is used. For IV therapy, no adjustment needed.
No specific dose adjustment required for erythromycin ethylsuccinate in pregnancy solely due to pregnancy. Pharmacokinetic changes in pregnancy (increased volume of distribution, enhanced clearance) may reduce serum levels, but typical dosing regimens (e.g., 400 mg q6h for adults) remain effective. Monitor clinical response. For severe infections, consider serum level monitoring if available.
Category C
Category C
E-MYCIN E (erythromycin ethylsuccinate) is a macrolide antibiotic with bacteriostatic activity against gram-positive cocci and atypical pathogens. It is a prodrug that is hydrolyzed to active erythromycin. Administer on an empty stomach for optimal absorption. It may prolong QT interval; use with caution in patients with electrolyte disturbances or concurrent QT-prolonging drugs. Monitor for hepatotoxicity, especially in patients with pre-existing liver disease. It is a strong inhibitor of CYP3A4, increasing levels of statins, warfarin, and other drugs.
Erythromycin (E.E.S.) is a macrolide antibiotic that inhibits bacterial protein synthesis. It is a CYP3A4 inhibitor and can increase levels of statins, warfarin, and immunosuppressants. QT prolongation risk; avoid with other QTc-prolonging drugs. Administer on empty stomach for best absorption, but can be taken with food if GI upset occurs. Not effective against Haemophilus influenzae in children due to resistance.
Take this medication exactly as prescribed, usually every 6 to 8 hours, on an empty stomach (1 hour before or 2 hours after meals).Do not crush or chew the tablets; swallow them whole with a full glass of water.Complete the full course of therapy even if you feel better to prevent antibiotic resistance.Avoid grapefruit juice as it may increase the effects and side effects of this medication.Contact your doctor immediately if you experience jaundice, dark urine, severe abdominal pain, or signs of liver problems.Inform your doctor about all medications you are taking, especially statins, warfarin, or other drugs metabolized by CYP3A4.Use effective contraception if you are of childbearing age; this medication may reduce the effectiveness of hormonal contraceptives.If you miss a dose, take it as soon as you remember. If it is almost time for the next dose, skip the missed dose and continue your regular schedule. Do not double the dose.
Take each dose with a full glass of water on an empty stomach (1 hour before or 2 hours after meals) unless stomach upset occurs, then may take with food.Complete the full course even if you feel better to prevent resistance.Avoid grapefruit juice during treatment as it may increase side effects.Report immediately any signs of liver problems (yellowing skin/eyes, dark urine, persistent nausea) or irregular heartbeat.Do not take with antacids containing aluminum or magnesium; separate by at least 2 hours.